The present invention relates to apparatus for severing or clipping and deforming the end convolutions or outermost convolutions of helical binders for stacks of loose leaves. More particularly, the invention relates to improvements in apparatus of the type wherein portions of both end convolutions of a helical binder are converted into loops or analogous configurations which surround the next-to-the-outermost convolutions, i.e., the convolutions which are adjacent (neighboring) to the end convolutions.
U.S. Pat. No. 3,568,729 to Freundlich et al. discloses an apparatus which converts portions of end convolutions of a helical binder into loops surrounding the neighboring (next-to-the-outermost) convolutions. The purpose of such loops is to prevent extraction of the binder from the openings or perforations of the leaves, to prevent interlacing of neighboring binders, and to reduce the likelihood of injury to the user of the pad. A drawback of the patented apparatus is its complexity and high initial and maintenance cost. Furthermore, the patented apparatus is prone to malfunction so that its operation must be monitored by attendants in order to reduce the number of rejects. In fact, special hand-operated machines have been designed to treat and repair the rejects of the patented apparatus, i.e., to put the rejects into a state in which they can be sold to customers.
One of several reasons for complexity and unreliability of the patented apparatus is that is wire severing and loop forming instrumentalities have been designed and assembled without taking into consideration the curvature of those portions of the end convolutions of the helical binder which are to be converted into loops. It has been found that, during the formation of loops, those portions of end convolutions which are about to be deformed tend to become entangled with other portions of the binder or abut against such other portions to thus prevent the formation of satisfactory loops.
Other references of which applicants were aware at the time of filing of the present application and which belong to the art of making and inserting helical binders for pads, note books or the like include U.S. Pat. Nos. 1,942,026, 1,985,776, 2,051,477, 2,058,272, 2,142,817, 2,161,689, 2,961,012, 2,995,157, 3,133,562, 3,134,406, 3,251,385, 3,404,711, 3,467,150, 3,520,334, 3,526,415, 3,568,729, 3,818,954, 3,826,290 and 3,972,109.